In recent years, a broadband communication line such as an ADSL (Asymmetric Digital Subscriber Line) which can perform high-speed data transmission is in widespread use. The ADSL is characterized in that a metallic cable same as a telephone line is used as a fine for a subscriber, whereby the identical line can be used for both an analog telephone service and a network connection service. That is, by inserting a frequency division filter called a splitter between the communication line and a communication terminal equipment, the line for transmitting a voice band signal can be separated from the line for transmitting digital data.
When the same line is used for the analog telephone service, various structures such as “ADSL modem+splitter+computer”, “ADSL modem+splitter+router” and the like can be considered as the structure of subscriber's equipments. On one hand, for example, the structure that the ADSL modem and the splitter are unified can be considered as an ADSL gateway which is used in consideration of common use with the telephone service.
In the ADSL gateway like this, for example, a modular jack is provided so that an analog telephone can be connected to the line which is used to transmit the voice band signal, whereby communication can be performed by connecting a communication apparatus such as the telephone or a facsimile machine to the modular jack.
Moreover, a CSMA/CD (Carrier Sense Multiple Access with Collision Detector) connection interface such as Ethernet™ is provided in the ADSL gateway so as to achieve high-speed digital communication. Thus, by connecting a PC (personal computer) or the like to the CSMA/CD interface, data can be downloaded at high speed from a WWW server or the like. However, as the interface between the ADSL gateway and network equipments such as the PC and the like, an interface such as a USB (Universal Serial Bus) or the like is used in addition to the CSMA/CD interface.
The terminal equipment such as the PC which is used by connecting it to the server can achieve high-speed communication, and on one hand the terminal equipment such as the telephone or the facsimile device which performs transmit/receive with a destination terminal equipment in real time via a line switching network (analog communication path) uses an analog band. In an analog facsimile procedure, although any problem does not likely occur when merely black-and-white binary image data or so is transmitted, a problem that it takes a long time occurs when color image data of a large amount (according to a JPEG (Joint Photographic Experts Group) format or the like) taken by a digital camera or the like is transmitted,
In order to transmit communication data such as the image data or the like at high speed, the facsimile machine is connected to the CSMA/CD interface, the image data is uploaded to a file server in the form of packet (e.g., using a protocol such as FTP (File Transfer Protocol), HTTP (HyperText Transport Protocol) or the like), and the uploaded image data is then downloaded from the server by the destination terminal equipment. However, in this case, there occur problems that it is necessary for the receiving side to take the trouble to access the file server to receive the data and that an advantage of real-time communication is lost. Besides, when the destination address of the receiving side is notified to the server and when the data is downloaded on the initiative of the receiving side, a mechanism to notify the receiving side of the data having been uploaded is necessary. For this reason, it is difficult to achieve the communication by a simple operation of merely designating a telephone number of a communication destination as in the conventional facsimile machine.
In consideration of this point, Japanese Patent Application Laid-Open No. H10-107938 (called document 1 hereinafter) discloses the technique to perform image communication via a server on an IP network. That is, in the document 1, a first terminal equipment on an image transmitting side calls the server including the first terminal equipment, connects with the computer network via the server including the first terminal equipment, and further designates a second terminal equipment being the receiving side of the image communication. Then, a server of the network including the second terminal equipment calls the second terminal equipment, the first terminal equipment sends the image data to the server including the second terminal equipment via the computer network in a form suitable for this network, and the server including the second terminal equipment converts the received image data of the form suitable for the computer network into facsimile image data and further sends the converted image data to the second terminal equipment via a public network, whereby the second terminal equipment reproduces an image from the received facsimile image data.
Further, Japanese Patent Application Laid-Open No. H9-247334 (called document 2 hereinafter), Japanese Patent Application Laid-Open No. H10-133967 (called document 3 hereinafter) and the like propose many kinds of methods of transmitting an image in the form of electronic mail by inputting an Internet address of a communication destination.
Furthermore, Japanese Patent Application Laid-Open No. 2000-354127 (called document 4 hereinafter), Japanese Patent Application Laid-Open No. 2001-197279 (called document 5 hereinafter) and the like propose a method of relaying facsimile image transmission in real time on the Internet by applying ITU-T (International Telecommunication Union Telecommunication Standardization Sector) Recommendation T.38.
(Document 1)
    Japanese Patent Application Laid-Open No. H10-107938(Document 2)    Japanese Patent Application Laid-Open No. H9-247334(Document 3)    Japanese Patent Application Laid-Open No. H10-133967(Document 4)    Japanese Patent Application Laid-Open No. 2000-354127(Document 5)    Japanese Patent Application Laid-Open No. 2001-197279
However, in the document 1, it is necessary in the terminal equipment on the transmitting side to perform dial-up connection with the server, perform a log-in process including an authentication procedure and the like, and then input a terminal equipment number of the transmission destination. Therefore, it is impossible to perform the image transmission only by inputting the telephone number as in the conventional facsimile machine.
Further, in the documents 2 and 3, it is necessary to input a mail address when the image data is transmitted via the Internet. Besides, since the image is transmitted as the electronic mail, the image data are accumulated in a server, whereby a problem that it is necessary for the receiving side to receive the image data by accessing the server according to an electronic mail reading protocol such as POP (Post Office Protocol) or the like occurs.
Furthermore, in the documents 4 and 5, it is necessary to provide a gateway dedicated for processing the protocol of ITU-T Recommendation T.38. Besides, since an ordinary telephone line is used between the terminal equipment and the Internet, transmission speed is the same as that in case of facsimile transmission utilizing a conventional telephone switching network.
Besides, the conventional communication technique has been developed independently in regard to each of a facsimile field, an IP communication field and the like, whereby there is a problem that the respective technical fields are not yet integrated adequately. For example, a user is required to be familiar independently with each of an operation specific in the facsimile machine and operations on the PC specific in various IP communication. Further, as seen from the view of manufacturing corporations which provide hardware/software, it is necessary to provide completely different software/hardware in regard to each of the facsimile field, the IP communication field and the like, although data communication in each technical field is not so different essentially. Within this meaning, it is desired to, by favorably integrating the necessary technical parts of the respective fields such as the facsimile field, the IP communication field and the like, enable the data communication which can be easily operated, is excellent in versatility, and can be easily applied inexpensively.